Yes;
Make a final sync of your data and other information. Then uninstall the version of palm Desktop that you are using. After that, make a copy of the C:\Program Files\palmone or Handspring\(user name) Backup and Archive folders and place it on your desktop or somewhere else. Then install the version of Palm Desktop that comes with the 680. You will want to do a check at the developer's sites for all of the third party apps that you have on your 600 and get the hi-res and updated versions. I would caution against doing much until you see all that the 680 can do as its more capable and some things are done natively on the 680 that are not done so on the 600.